Fire retardant fine particulate expandable styrene polymers

Abstract

Fire retardant, expanded styrene polymer shaped objects are perpared by: (a) mixing styrene monomer or a mixture thereof with at least one comonomer, an expanding agent and a fire retardant, organic halogen compound in a aqueous dispersion; (b) adding to (a) either before or during polymerization from about 0.0001 to 0.1 percent by weight esters soluble in the organic phase of (a), these esters of aliphatic dicarboxylic acids and aliphatic epoxy alcohols having at least 11 carbon atoms; (c) polymerizing the aqueous dispersion of (a) and (b) using radical forming initiators at a temperature of about 80 DEG to 130 DEG C.; (d) separating bead polymers having diameters between about 0.4 and 3 mm; (e) pre-foaming the beads; (f) ageing the pre-foamed beads; and (g) final forming the aged and pre-foamed beads in a pressure resistant mold.

We claim: 
     
       1. In a process for the preparation of shaped bodies based on expanded styrene or a mixture thereof with at least one monomer copolymerizable therewith, the addition of an expanding agent and a five retardant organic halogen compound, pre-forming of the resulting expandable particles, ageing of the formed particles, and molding thereof in a pressure resistant mold, the improvement comprising: carrying out the polymerization in the presence of about 0.0001 to 0.1 percent by weight based on the weight of said styrene or mixture thereof of esters of aliphatic dicarboxylic acids and aliphatic epoxy alcohols, said esters having at least 11 carbon atoms and said esters soluble in said monomers and comonomers. 
     
     
       2. The process of claim 1, wherein said polymerization is suspension polymerization in the presence of radical initiators and said esters are added before polymerization. 
     
     
       3. The process of claim 1, wherein said polymerization is suspension polymerization in the presence of radical initiators and said esters are added during polymerization. 
     
     
       4. The process of claim 1, wherein said esters are selected from the group consisting of glutaric acid-bis-glycidylester, adipic acid-bis-glycidylester, pimelic acid-bis-glycidylester, suberic acid-bis-glycidylester, azelaic acid-bis-glycidylester, sebacic acid-bis-glycidylester, dodecanoic-diacid-bis-glycidylester, brassylic acid-bis-glycidylester and 2,2,4(2,4,4)-trimethyl-adipic acid diglycidylester. 
     
     
       5. The process of claim 1, wherein said esters have a concentration of about 0.001 to 0.05. 
     
     
       6. The shaped bodies obtained by the process of claim 1.